<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>计算圆的面积和周长</title>
    <script>
        function getArea(r) {
            return Math.PI * Math.pow(r, 2)
        }

        function getLong(r) {
            return Math.PI * 2 * r
        }

        console.log('半径为5的圆的面积是：\n' + getArea(5))
        console.log('\n半径为5的圆的周长是：\n' + getLong(5))
    </script>
</head>

<body>

</body>

</html>